Minnesota Plant Diseases. 3 



life-history. All of those diseases which are at present success- 

 fully combated have been dealt with only after a thorough 

 knowledge of their habits. The treatment of oat smut, for in- 

 stance, is based on the knowledge that infection of the oat plant 

 takes place when the plant is in the seedling stage and from 

 spores found usually clinging to the oat grains. 



The predisposition of plants toward disease is a subject 

 which at this point is to be dealt with only in passing, and will 

 receive more detailed attention in later chapters. 



Part I. of this work will deal in general with those groups of 

 plants, particularly the fungi, which furnish the causes of dis- 

 eases in plants and with general methods of combating diseases, 

 etc. Part II. will be given up to a consideration of specific dis- 

 eases of Minnesota plants. 



